All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Therefore, if the deceased did not leave any other heirs except those mentioned in the question, then his mother gets one-sixth of the inheritance as her legal share due to the existence of children of the deceased as Allaah says (what means): {And for one’s parents, to each one of them is a sixth of his estate if he left children.}[Quran 4:11]
His wife gets one-eighth as her legal share due to the existence of children; Allaah says (what means): {But if you leave a child, then for them [i.e. the wives] is an eighth of what you leave, after any bequest you [may have] made or debt.} [Quran 4:12]
His daughter gets a half as her legal share as Allaah says (what means): {And if there is only one [daughter], for her is half}[Quran 4:11]
The remainder should be divided among the two full-sisters equally by Ta’seeb (by virtue of having a paternal relation with the deceased and not having an allotted share, so they get what is left after the allotted shares have been distributed) as it is confirmed that the Prophet gave the sister the remainder of the inheritance after the share of the daughter and the son's daughter. The Hadeeth was narrated by Huzayl ibn Shurahbeel and reported by Al-Bukhari. It is for this reason that the scholars considered the sister as an heir by Ta'seeb along with the daughters and the granddaughters and she takes whatever remains of the inheritance after its division.
The grandmother does not get any share from the inheritance because she is prevented by the existence of the mother. Ibn Al-Munthir said: “The scholars agreed in a consensus that the mother prevents her mother and the mother of the father from the inheritance.”
Therefore, the inheritance should be divided into 48 shares. The mother of the deceased gets one-sixth which is 8 shares, his wife gets one-eighth which is 6 shares, the daughter gets a half which is 24 shares, and the two full-sisters get the remainder, which is 10 shares, which means that each one of them gets 5 shares.
Allaah Knows best.